1. Field of the Invention
This invention relates in general to the field of medical fluid connectors, and in particular to a check valve for use in a medical Y-site connector.
2. Description of the Related Art
Intravenous delivery of fluids has become an important aspect of modern medicine. Infusion systems are used to deliver hydrating and nourishing fluids, antibiotics, anesthetics, and other medications to patients. Infusion systems typically include a bag of fluid joined to a fluid line which is connected to an IV needle or catheter inserted into a patient's blood vein, thereby allowing the fluid to be dripped from the bag and into the patient.
In many infusion systems, Y-sites are placed in the fluid line, between the fluid bag and the needle or catheter, to provide a second path through which other fluids or drugs can be injected into the infusion system. Standard Y-sites are so named because a fork is created between a main lumen having an input port for introducing infusion liquid and a secondary lumen with an injection port for injecting medication therethrough. The main lumen typically is configured to handle a constant or near-constant flow, and the secondary lumen is configured to handle an intermittent or periodic flow. The common lumen and the secondary lumen are typically coaxial, and thus the boundary between the common and secondary lumens is the region of confluence between the fluids flowing through the main and secondary lumens. An outlet in the Y-site is located at a distal end of the common lumen.
In some cases, the distally directed fluid flow in the common lumen is slower than a periodic burst of fluid introduced into the secondary lumen. This may create fluid pressure in the region where all three lumens are joined that is greater than the fluid pressure in the main lumen upstream of this juncture, causing a volume of fluid (e.g. medication) that has been injected through the secondary lumen to flow upwardly through the main lumen towards (and possibly into) an IV bag or another medical implement. This retrograde flow can dilute and delay delivery of the full dose of medication to the patient. While all of the medication may eventually reach the patient, it may not do so as quickly as might be desired.